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The increased use of alternative fuels has been linked to performance deterioration of injectors and engines as a result of internal diesel injector deposits (IDID). The present paper investigates fuel composition impact on injector tendency to blockage. Three main areas were investigated : (1) deposits linked to paraffins and aromatics content; (2) deposits linked to biodiesel composition using fatty acid methyl esters (FAME) and hydrotreated vegetal oil (HVO); and (3) deposits linked to the presence of additives (Dodecenylsuccinic anhydride DDSA, Dodecenyl Succinimid DDSI and Sodium Naphthenate). A deposit formation method was developed for the injection bench in order to discriminate the impact of fuels on system performance in terms of fuel volume injected, injection duration and stability. Three operation conditions were tested to represent low, intermediate and high load. In addition, the influence of soaking time and injector heating temperature was evaluated.

The increased use of alternative fuels has been linked to deterioration in performance of fuel injection systems as a result of insoluble deposit formation. Here, the impact of Diesel/biodiesel blends formulation and temperature on the oxidation stability was studied based on total acid number (TAN), density, viscosity and surface tension. We have compared fuel oxidation during storage with fuel oxidation into the fuel injection system (FIS) and determined the most important physical-chemical parameters that could be used to follow fuel oxidation on-board. Based on the results obtained, a satisfactory correlation between storage oxidation and fuel on-board degradation was observed. Biodiesel fuel tends to deteriorate during delivery and storage before refueling. Also, fuel ageing on-board is equivalent to 4-5months of storage which means Biodiesel has impact on fuel injection system with long-term storage/parking after high or high-low alternating load operation.

The use of biodiesel has risen worldwide in the last decade. Different countries use different biodiesel feedstocks which will depend on the resources available locally. Some problems due to biodiesel content and feedstock quality have been pointed out in the literature, which include cold flow properties issues of several methyl esters, especially Palm Methyl Ester (PME). The present work was carried out on diesel-biodiesel blends from 0 to 30%v/vPME in order to evaluate the impact of crystals formation on fuel filter plugging using a rig test. The fuel was maintained at 5°C and 20°C during soaking. The crystal particles formation was evaluated by the Turbiscan™ technique (based on multiple light scattering with near infra-red light), followed by particles mass weight determination by filtration. The fuel was then evaluated in the test rig until performances degradation in terms of fuel flow rate and filter pressure drop.